Nonlinear Optical Gratings

Abstract

This chapter presents the results obtained on recording nonlinear gratings in azopolymers. It should be recalled that a nonlinear grating is a system, a polymer film in our case, in which the polar orientation induced by an electric field has a spatial modulation, resulting in a modulation of the nonlinear susceptibility tensor. When a light beam hits a diffraction grating, a redistribution of the intensity of the transmitted light is observed, a sequence of diffraction maxima in increasing order (±1, ±2, …) appearing on both sides of the propagation direction of the incident beam (which determines the direction of the 0 order) as we move away from the incident direction.